The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.
FIG. 1 is a block diagram of a conventional communication system using a quantum key distribution system.
Referring to FIG. 1, the conventional communication system using a quantum key distribution system includes a quantum key distribution system transmitter 110, a quantum key distribution system receiver 120, a plurality of transmitting apparatuses 130, 135, and a plurality of receiving apparatuses 140, 145.
The quantum key distribution system transmitter 110 (hereinafter referred to as “Alice”) and the quantum key distribution system receiver 120 (hereinafter referred to as “Bob”) utilize a public channel and a quantum channel to generate a quantum key which they share.
The transmitting apparatuses 130, 135 and the receiving apparatuses 140, 145 receive the quantum keys generated by and distributed from Alice and Bob, respectively, and they send and receive data or data packets encrypted by using the quantum keys. In practice, the transmitting apparatuses and the receiving apparatuses have a two-way secure communication function to respectively perform data transmission and reception functions at the same time or to perform simultaneous encryption and decryption functions. However, in the present disclosure, for the sake of convenience, secure communication equipments that are linked with Alice in the quantum key distribution system are referred to as transmitting apparatuses, and secure communication equipments that are linked with Bob in the quantum key distribution system are referred to as receiving apparatuses.
The existing communication system utilizing a quantum key distribution system has some trouble, when it has multiple transmitting apparatuses or receiving apparatuses and where these apparatuses request quantum keys from Alice or Bob at a similar time point. When or whenever the multiple transmitting apparatuses or the respective receiving apparatuses respectively make the nearly simultaneously quantum key requests to Alice or Bob for the quantum key, Alice and Bob remain inoperative for the next request until a previous quantum key request is completely served for the transmitting apparatuses and the receiving apparatuses before processing the next request. Due to their suspended processing of the subsequent request until fulfilling the previous one of the multiple distribution requests for the quantum key, when supplying the quantum key to the multiple transmitting apparatuses or receiving apparatuses, Alice alone and Bob are constrained by a delay of supply in distributing the quantum key.
Further, when Alice or Bob has depleted all of quantum keys in their storages to fulfill the requests of a plurality of transmitting apparatuses or receiving apparatuses, the existing communication system needs to replenish the storages with new quantum keys, resulting in inconvenient breaks of the quantum key supplement to by the transmitting apparatuses or receiving apparatuses.